Inertia locking system and collapsible seat with the locking system

A collapsible seat for a vehicle comprising:

• a seat back supported to a body floor of a vehicle;
• a seat cushion pivotally supported to said seat back so as to be tiltable;
• said seat back being provided with a substantially C-shaped leg portion;
• said leg portion being attached to said seat cushion with an opening thereof facing upwardly;
• said leg portion having a lower section;
• and
• an inertia locking system for locking said seat relative to said body floor;
• said inertia locking system comprising:
• a pedestal mounted on said body floor and having a substantially U-shaped receiving port;
• said receiving port having a first obliquely, upward facing opening for receiving said lower section of said leg portion;
• a substantially U-shaped clip having a second opening for receiving said lower section of said leg portion;
• said clip being received in said first opening of said receiving port and attached to said pedestal with said second opening thereof facing obliquely and upwardly;
• said second opening of said clip having a width slightly narrower than a diameter of an axis of said lower section of said leg portion;
• a latch formed into a substantially inverted J-shape;
• said latch having a lower base portion, a curved upper portion, and a jaw portion protruding from said lower base portion;
• said latch being pivotally supported at said lower base portion thereof to a side portion of said pedestal by a pivot pin with said upper portion thereof facing said receiving port and with said jaw portion protruding beyond an inner surface of said receiving port;
• and
• a torsion coil spring for always biasing said latch away rearward from said receiving port;
• said torsion coil spring having a coiled spring portion and first and second ends;
• said coiled spring portion being mounted on an axis of said pivot pin;
• said first end of said torsion coil spring being fastened to a position of said side portion of said pedestal which is close to a rear side of said pivot pin;
• said second end of said torsion coil spring being fastened to a side of said latch;
• wherein when said lower section of said leg portion is received in said first opening of said receiving port and said second opening of said clip, said lower section of said leg portion kicks said jaw portion so as to rotate said latch in the opposite direction to the direction in which said latch is always biased by said torsion spring, whereby said lower section of said leg portion is positively caught by said upper curved portion of said latch.